avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/powerpc/cpu/ppc4xx/spl_boot.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2013 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <spl.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Return selected boot device. On PPC4xx its only NOR flash right now.
+ */
+u32 spl_boot_device(void)
+{
+	return BOOT_DEVICE_NOR;
+}
+
+/*
+ * SPL version of board_init_f()
+ */
+void board_init_f(ulong bootflag)
+{
+	/*
+	 * First we need to initialize the SDRAM, so that the real
+	 * U-Boot or the OS (Linux) can be loaded
+	 */
+	initdram(0);
+
+	/* Clear bss */
+	memset(__bss_start, '\0', __bss_end - __bss_start);
+
+	/*
+	 * Init global_data pointer. Has to be done before calling
+	 * get_clocks(), as it stores some clock values into gd needed
+	 * later on in the serial driver.
+	 */
+	/* Pointer is writable since we allocated a register for it */
+	gd = (gd_t *)(CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_GBL_DATA_OFFSET);
+	/* Clear initial global data */
+	memset((void *)gd, 0, sizeof(gd_t));
+
+	/*
+	 * get_clocks() needs to be called so that the serial driver
+	 * works correctly
+	 */
+	get_clocks();
+
+	/*
+	 * Do rudimental console / serial setup
+	 */
+	preloader_console_init();
+
+	/*
+	 * Call board_init_r() (SPL framework version) to load and boot
+	 * real U-Boot or OS
+	 */
+	board_init_r(NULL, 0);
+	/* Does not return!!! */
+}